A manufacturing process for manufacturing semiconductor substrates (hereinafter, simply referred to as “substrates”) conventionally involves various types of processing that is performed on the substrates by substrate processing apparatuses. For example, processing such as etching is performed on a surface of a substrate having a resist pattern on its surface by supplying a chemical liquid to the substrate. After the supply of the chemical liquid, other processing is further performed, such as rinse processing for supplying pure water to the substrate to remove the chemical liquid on the surface and dry processing for removing the pure water on the surface by rotating the substrate at high speed.
When rinse processing using pure water and dry processing are performed in this order on a substrate having a large number of fine pattern elements on its surface, a liquid level of pure water is formed between each two adjacent pattern elements in the course of drying. In this case, the surface tension of the pure water acts on the pattern elements and may collapse the pattern elements. In view of this, Japanese Patent Application Laid-Open No. 2011-124313 discloses a technique for replacing a rinse liquid that remains in recessed portions formed between circuit patterns of a substrate with a filler (polymer) to fill the recessed portions with the filler and solidify the filler, and then removing the filler from the surface of the substrate by plasma processing. Japanese Patent Application Laid-Open No. 2013-258272 discloses a technique for replacing a rinse liquid that adheres to the surface of a substrate having a raised shape pattern with a solution made by dissolving a solute in a solvent, then vaporizing the solvent to precipitate the solute on the surface of the substrate, and then subliming the precipitated solute.
When a water-based polymer solution, for example, is used as a filler solution in the technique (also called “Sacrificial Polymer Fill (SPF)”) for filling spaces between a large number of pattern elements with a filler solution and subliming the solidified filler by dry etching or other techniques as described above, there is no flash point and thus a high level of safety is ensured. Also, a polymer that is dispersed to the surroundings can be readily cleaned with water when the polymer solution is applied to the substrate, and therefore it is possible to ensure ease of maintenance and suppress the manufacturing cost of devices.
The above techniques use a filler solution with a relatively low viscosity in order to allow a filler to diffuse under its own weight into spaces between pattern elements. Also, in order to improve the throughput of dry etching, substrates are rotated at, for example, relatively high revolutions per minute (rpm) such as 1500 rpm after the supply of the filler solution to the substrates, and therefore the filler solution is spun off and the thickness of a layer of the filler solution is reduced. However, deformation of pattern elements may occur in the above processing. Such deformation of pattern elements is particularly evident in the case of using a water-based polymer solution with a high surface tension.